The present invention relates to interfolding methods and apparatuses, and more specifically to the transfer of sheets onto interfolding rolls of the interfolding methods and apparatuses.
Various combinations and types of rolls can be present in an interfolding apparatus. A typical interfolding apparatus includes at least two interfolding rolls, at least one knife or cutting roll, and at least one feed roll for pulling streams of web material into the interfolding apparatus. The web material is generally cut at or near the knife rolls and then travels to a bed roll, which may include a vacuum to help guide the web through its path. From the bed roll, the web travels to a lap roll to overlap the sheets, which are eventually transferred to a nip between the interfolding rolls.
In known interfolder designs where a multi-fold stack of sheets is desired (e.g., sheets that include two folds, forming three panels, where the third panel of one sheet is interfolded with the first panel of another sheet), the lap roll drives the web of sheets to a slow-down roll that travels at a speed ⅓ slower than the speed of the lap roll. The slow down roll delays the movement of a sheet to allow the next consecutive sheet to overlap the trailing ⅓ of the first sheet. Thus, in the known interfolders, the transfer and overlap of the sheets is done at an intermediate station before the overlapped sheets are transferred to the folding rolls. The addition of the slow down roll adds to the overall size, expense, and complexity of the interfolder. It is thus desirable to provide an interfolder capable of forming multi-fold stacks of sheets that is more compact, simpler to operate, and simpler to manufacture.